Both part 4 and part 11 make implicit assumptions about the existence of a "AggregateConfiguration" data type which is used in AggregateFilter and ReadProcessedDetails structure. This type however is not formally defined in any part of the specification.

I am also concerned about the semantics of the type member "useSeverCapabilitiesDefaults". Since the latest release candidate of part 11 does no longer specify "PercentDataBad" et al. in the server capabilities object and since a server does no longer need to provide a HistoricalDataConfiguration (which includes an aggregate configuration) for each historical variable, a client may not know which configuration defaults a server applies. Additionally, it is not clear which AggregateConfiguration a server should use if "useSeverCapabilitiesDefaults" is set to false and the HistoryRead request contains more than one node with each having different AggregateConfigurations.